Using WordPress ‘is_upload_space_available()’ PHP function
Determines if there is any upload space left in the current blog’s quota.
HTTPS
Using WordPress ‘is_trackback()’ PHP function
Determines whether the query is for a trackback endpoint call.
Using WordPress ‘is_theme_paused()’ PHP function
Determines whether a theme is technically active but was paused while loading.
Using WordPress ‘is_textdomain_loaded()’ PHP function
Determines whether there are translations for the text domain.
Using WordPress ‘is_tax()’ PHP function
Determines whether the query is for an existing custom taxonomy archive page.
Using WordPress ‘is_tag()’ PHP function
Determines whether the query is for an existing tag archive page.
Using WordPress ‘is_subdomain_install()’ PHP function
The `is_subdomain_install()` function in WordPress determines if a subdomain configuration is enabled in a multisite setup
Using WordPress ‘is_ssl()’ PHP function
The article "Using WordPress `is_ssl()` Function" provides an overview of how to use the `is_ssl()` function in WordPress to determine if the current page is being served over SSL and…
Using WordPress ‘is_singular()’ PHP function
Determines whether the query is for an existing single post of any post type (post, attachment, page, custom post types).